Liquid-tight and concrete-tight fitting for PVC jacketed metal-clad electrical cable

ABSTRACT

A liquid-tight and concrete-tight electrical fitting for securing PVC jacketed metal clad (PVC-MC) electrical cable to an electrical box or panel. The electrical fitting includes a tubular fitting body having a threaded inbound and outbound end, an MC ring, a grommet, a bushing, a sealing ring, a locknut, and a gland nut. The grommet includes an inbound end with a conical outer surface and an outbound end with a flat abutment surface. A conical inner surface is provided on the bushing for engaging the conical outer surface of the grommet. The MC ring is a continuous ring including an inbound end, an outbound end, a ring portion, and one or more fingers extending from the ring portion. The fitting facilitates liquid-tight and concrete-tight connection and proper electrical grounding of PVC-MC cable to an electrical box or panel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to provisional U.S. Application No.62/271,392, filed Dec. 28, 2015, and this application is aContinuation-In-Part of U.S. patent application Ser. No. 14/738,994filed Jun. 15, 2015 and still pending, the entire contents of which isincorporated herein by reference.

FIELD OF THE INVENTION

This invention relates to electrical fittings or connectors forconnecting electrical cables to a panel and specifically to aliquid-tight and concrete-tight fitting for connecting PVC jacketedmetal-clad electrical cable to an electrical box or panel.

BACKGROUND OF THE INVENTION

PVC jacketed metal-clad (PVC-MC) electrical cable is commonly used forconducting electrical supply in homes and residential buildings. PVC-MCcable typically includes a plurality of internal conductors within aninterlocked conductive armor layer covered by an outer jacket of PVC(polyvinyl chloride). The armor in many cases may serve as the groundingpath for the cable.

U.S. patent application Ser. No. 14/738,994, filed Jun. 15, 2015, andsharing common ownership with the present invention, disclosed anelectrical fitting that facilitated rain-tight connection and properelectrical grounding of PVC-MC cable to an electrical box or panel.

Although the parent application provided a rain-tight electrical fittingwith improved features for connecting PVC-MC cable to an electrical box,PVC-MC electrical cable is also rated for installation in concrete,which rating requires a fitting that is liquid-tight and concrete-tight.Accordingly, in the connection of PVC-MC cable to an outdoor electricalbox, it is important to achieve both a liquid-tight connection and aconcrete-tight connection while at the same time achieving a propergrounding path between the armor shell and the electrical box.

BRIEF SUMMARY OF THE INVENTION

The current invention is a liquid-tight and concrete-tight electricalfitting for securing PVC jacketed metal clad (PVC-MC) electrical cableto an electrical box or panel. The electrical fitting includes a tubularfitting body having a threaded inbound and outbound end, an MC ring, agrommet, a bushing, a sealing ring, a locknut, and a gland nut. Thegrommet includes an inbound end with a conical outer surface and anoutbound end with a flat abutment surface. A conical inner surface isprovided on the bushing for engaging the conical outer surface of thegrommet. The MC ring is a continuous ring including an inbound end, anoutbound end, a ring portion, and one or more fingers extending from thering portion. The fitting facilitates liquid-tight and concrete-tightconnection and proper electrical grounding of a wide range of PVC-MCcables to an electrical box or panel.

Objects and Advantages

A first object of the current invention is to provide an electricalfitting that enables liquid-tight and concrete-tight connection of PVCjacketed metal-clad electrical cable to an electrical box or panel.

A second object of the invention is to provide an electrical fittingthat creates secure grounding of PVC-MC electrical cable to the fittingand to an electrical box or panel.

A further object of the invention is to provide a liquid-tight andconcrete-tight electrical fitting that can accommodate a wide range ofcable sizes.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Reference is made herein to the accompanying drawings, which are notnecessarily drawn to scale, and wherein:

FIG. 1 is an exploded side view of a fitting for a PVC-MC cable inaccordance with embodiments of the invention.

FIG. 2 is a side view of a body member which forms a portion of thefitting of FIG. 1.

FIG. 3 is an end view of the body as taken from the right side of FIG.2.

FIG. 4 is a sectional view of the body taken along line 4-4 of FIG. 3.

FIG. 5 is a side view of a grommet which forms a portion of the fittingof FIG. 1.

FIG. 6 is an end view of the grommet.

FIG. 7 is a sectional view of the grommet taken along line 7-7 of FIG.6.

FIG. 8 is a side view of a sealing ring which forms a portion of thefitting of FIG. 1.

FIG. 9 is a sectional view of the sealing ring taken along line 9-9 ofFIG. 8.

FIG. 10 is an expanded view of a portion of the sectional view alongline 9-9 of FIG. 8.

FIG. 11 is an elevation view of a locknut which forms a portion of thefitting of FIG. 1.

FIG. 12 is a side view of the locknut.

FIG. 13 is a sectional view of the locknut taken along line 13-13 ofFIG. 11.

FIG. 14 is a side view of a nut which forms a portion of the fitting ofFIG. 1.

FIG. 15 is an end view of the nut.

FIG. 16 is a sectional view of the nut taken along line 15-15 of FIG.15.

FIG. 17 is an elevation view of an MC ring which forms a portion of thefitting of FIG. 1.

FIG. 18 is a side view of the MC ring.

FIG. 19 is a plan view of a blank that is used to form the MC ring.

FIG. 20 is a sectional view of the electrical fitting assembled andconnected to an electrical box with an electrical cable insertedtherein.

FIG. 21 is a side view of an alternate embodiment of a grommet accordingto the present invention.

FIG. 22 is a side view of a bushing that forms a portion of the fittingof the present invention.

FIG. 23 is an exploded isometric view of a second embodiment of afitting for PVC-MC cable in accordance with embodiments of theinvention.

FIG. 24 is an end view of the electrical fitting with an electricalcable inserted therein.

FIG. 25 is an isometric view of a PVC-MC electrical cable with an endportion of the PVC jacket stripped off the cable.

FIG. 26 is a sectional view of the electrical fitting taken along line26-26 of FIG. 24.

FIG. 27 is an exploded isometric view of a third and preferredembodiment of an electrical fitting for PVC-MC cable in accordance withembodiments of the invention.

FIG. 28 is a side view of a body member which forms a portion of thefitting of FIG. 27.

FIG. 29 is a sectional view of the fitting body taken along line 29-29of FIG. 28.

FIG. 30 is a side view of a grommet which forms a portion of the fittingof FIG. 27.

FIG. 31 is an isometric view of the grommet.

FIG. 32 is an end view of the grommet.

FIG. 33 is a sectional view of the grommet taken along line 33-33 ofFIG. 32.

FIG. 34 is an isometric view of an MC ring which forms a portion of thefitting of FIG. 27.

FIG. 35 is an isometric view of the MC ring from the opposing end.

FIG. 36 is a side view of a bushing which forms a portion of the fittingof FIG. 27.

FIG. 37 is a front elevation view of the bushing.

FIG. 38 is a sectional view of the bushing taken along line 38-38 ofFIG. 37.

FIG. 39 is an isometric view of the bushing.

FIG. 40 is a side view of the electrical fitting of FIG. 27 in anassembled state according to the present invention.

FIG. 41 is a sectional view of the assembled electrical fitting takenalong line 41-41 of FIG. 40.

DETAILED DESCRIPTION

The present invention is an electrical fitting for PVC jacketed MetalClad (PVC-MC) electrical cable. As shown in FIG. 1, the electricalfitting 20 includes a fitting body 22 having an inbound end 24 and anoutbound end 26. The fitting includes an MC ring 28 and a grommet 30secured to the inbound end 24 by a gland nut 32 and a sealing ring 34that will be secured to the outbound end 26 by a locknut 36 after theoutbound end is connected to an electrical panel or electrical box (notshown).

Referring to FIGS. 2-4, the fitting body 22 includes a central flange 38with flat surfaces or facets 40 thereon enabling gripping by a wrench orsimilar tool, a threaded nose portion 42 extending from the outbound end26 and a threaded tubular portion 44 at the inbound end 24.

As shown in FIG. 4, the fitting body 22 includes an inbound channel 46at the inbound end 24, a necked-down channel 48 formed by a rampedsurface 50 circumscribing the interior of the body, an inner channel 52having an inner diameter smaller than that of the inbound channel 46,and an outbound channel 54 at the outbound end 26. The body 22 includesa lip 56 circumscribing the interior of the body at the outbound end anddefining an opening 57 therein.

With reference to FIGS. 5-7, the grommet 30 is substantially cylindricalshaped and includes a body 58 having an inbound end 60, an outbound end62, and a central bore 64 there through. A lip 66 extends inward fromthe inner periphery 67 of the grommet 30 at the inbound end. As shown inFIG. 7, the lip 66 is triangular-shaped in cross-section. The grommet ispreferably constructed of elastomeric material. Most preferably it ismolded in one piece of SANTOPRENE®, a synthetic rubber elastomericmaterial available from Monsanto Company Corporation of St. Louis, Mo.

Referring to FIGS. 8-11, the sealing ring 34 includes a torus-shapedbody 68 with an inbound end 70, an outbound end 72, and a central bore74 formed by a circular inner surface 76 on the sealing ring. Threethread engagement tabs 78 extend from the circular inner surface 76 ofthe sealing ring. Each of the tabs 78 include a base 80 and rise to asharp point or apex 82 that is aligned along the central axis 84 of thesealing ring 34. The sealing ring 34 is preferably constructed of aplastic material. Most preferably it is molded in one piece of Dow993/NT, a linear polyethylene (LPE) material available from Dow ChemicalCompany of Midland, Mich.

Referring to FIGS. 11-13, the substantially tubular locknut 36 includesan outer surface 86 and a plurality of lugs 88 extending from the outersurface. The locknut 36 further includes an inbound end 90, and outboundend 92, and an inner surface 94. A chamfered surface 96 is providedaround the inner periphery of the inner surface 94 at both the inboundend 90 and outbound end 92. As a result of the chamfered surfaces 96,the outer surface 86 is wider than the inner surface 94. The locknut 36includes an opening 98 therein. Preferably, the locknut is formed in onepiece of metal. Most preferably, the locknut is molded of zinc alloy.

With reference to FIGS. 14-16, the gland nut 32 includes an outerperiphery 101 and a plurality of flat surfaces 103 for enabling grippingby a wrench or similar tool. The gland nut 32 further includes aninbound end 105 and an outbound end 107. The gland nut 32 includes awide chamber 109 at the outbound end 107 and a through bore 111 at theinbound end 105. A chamfered surface 113 is provided around the interiorperiphery 115 at the outbound end of the nut. The interior surface ofthe nut at the outbound end 107 includes threads 117 thereon and a lip119 with a flat engagement surface 121 thereon.

Referring to FIGS. 17-19, the MC ring 28 is created from a flat metalblank 123 including a base 125 and a plurality of fingers 127 extendingfrom the base as shown in FIG. 19. The blank 123 includes a tab 129 onone end 131 and a groove 133 on the opposing end. The metal blank 123 isformed into a substantially cylindrical split ring 135 with a centralaxis 137 as shown in FIGS. 17 and 18. The fingers 127 include endportions 139 bent inwards or toward the central opening. The split ring135 includes an inbound end 141 and an outbound end 143, with thefingers 127 extending from the outbound end 143.

Referring to FIG. 20, with the gland nut 32 partially threaded onto thefitting body 22, the electrical fitting 20 of the present invention isoperated by inserting the outbound end 26 of the fitting body 22 throughthe knockout 145 of an electrical box 147. The sealing ring 34 is placedover the outbound end and the locknut 36 tightened thereon to secure theoutbound end 26 of the fitting 20 to the electrical box 147. Centralflange 38 of fitting body 22 limits the distance fitting 20 is insertedinto the electrical box. The end portion of the PVC jacket is firststripped off the cable. PVC-MC cable 149 is then inserted through bore111 at the inbound end 105 of the gland nut 32. The PVC-MC cable 149inserts through fitting body 22 until fingers 127 of MC ring 28 areengaged by the ramped surface 50 of fitting body. Gland nut 32 is thentightened upon threaded tubular portion 44 of fitting body 22 andcontinued to be tightened until flat engagement surface 121 of gland nut32 forces fingers 127 of MC ring 28 inward into grooves 151 of PVC-MCcable 149 and compresses grommet 30 until it deforms or molds around andenvelops the cable 149. The deformed grommet 30 creates a rain-tightseal between the MC cable 149, the MC ring 28, and the gland nut 32. Arain-tight seal is further created at the threaded engagement of glandnut 32 with the threads 44 on fitting body 22. The inward bent fingers127 of MC ring lock the electrical cable 149 to the inbound end 105 ofthe fitting 20 and the compressed sealing ring 30 creates a rain tightseal around the electrical cable. Conductors 153 from the electricalcable 149 pass easily through the outbound channel 54 and opening 57 atthe outbound end 26 of the fitting body 22.

A critical feature of the electrical fitting 20 is the ability to createproper grounding of the MC cable 149 to the fitting body 22 and thefitting body to the electrical box 147 while the fitting at the sametime creates a rain tight connection between the fitting 20 and thePVC-MC cable 149. The MC ring 28 is preferably constructed of springsteel to impart resiliency to the ring 28 and the fingers 127 extendingtherefrom. The fitting body 22, locknut 36, and gland nut 32 arepreferably constructed of an electrically conductive metal. Preferablythe fitting body, locknut, and gland nut are constructed of zinc alloy,stainless steel, or plated steel. Most preferably, the fitting body 22,locknut 36, and gland nut 32 are die-cast of zinc alloy. Thus, when thefitting 20 is fully assembled as shown in FIG. 20, the fingers 127 ofthe MC ring 28 securely grip the armor layer of the PVC-MC cable 149while the MC ring is securely seated against the fitting body 22 and thegland nut 32. Furthermore, the locknut 36 is securely connected to theoutbound end 26 of the fitting body 22 and the central flange 38 issecurely held against the electrical box 147. Thus, a proper groundingpath is established between the PVC-MC cable 149, the electrical fitting20, and the electrical box 147 thereby creating electrical continuitybetween the cable, fitting, and the electrical box. The properelectrical continuity is established at the same time a rain tightconnection is established between the electrical cable 149 and thefitting 20.

With reference to FIG. 21, a second embodiment of the grommet 30 bincludes a tubular body 58 having an inbound end 60, an outbound end 62,and a central bore 64 (see FIG. 23) there through. A flange 155 extendsoutward from the outer periphery 157 of the grommet 30 b at the inboundend 60. The flange 155 includes a ring engagement surface 159 which, asshown in FIG. 23, will engage the MC ring 28 in the assembly of the raintight fitting.

Referring to FIG. 22, an alternative embodiment of the rain tightfitting may also include a bushing 161. The bushing 161 includes atubular body 163 with an inbound end 165, an outbound end 167, and anose portion 169. A flange 171 extends outward from the outer periphery169 of the tubular body 163 of the bushing 161 at the outbound end 167.Flange 171 includes a flat abutment surface 173. As shown in FIG. 23, inthe rain tight fitting assembly the nose portion 169 of the bushing 161will extend through bore 109 of gland nut 32 and keep the bushingcentered with respect to the gland nut. In the assembly, the flatabutment surface 173 of bushing 161 engages the flat engagement surface121 (see FIG. 16) of the gland nut 32. The bushing 161 may beconstructed of metal or plastic. If constructed of plastic the bushingis preferably formed of polycarbonate. Most preferably, the bushing isconstructed of zinc alloy.

With reference to FIG. 23, the preferred embodiment of the fitting 180for PVC-MC cable includes a fitting body 22 with a sealing ring 34 and alocknut 36 on the outbound end 26 of the fitting body and an MC ring 28,grommet 28, bushing 161, and gland nut 32 on the inbound end 24 of thefitting body 22. Fingers 127 of MC ring 28 will extend into inboundchannel 46 of fitting body 22. Outbound end 62 of grommet 30 b seatswithin the base portion 125 of MC ring 28. Nose portion 169 of bushing161 extends through opening 57 in gland nut 32 and keeps the bushingcentered with respect to the gland nut. As gland nut 32 is tightened,flange 171 of bushing 161 seats against flange 155 of grommet 30 b andurges fingers 127 of MC ring 28 further into inbound channel 46 offitting body 22. Tightening locknut 36 onto outbound threads 42 andgland nut 32 onto inbound threads 44 of fitting body create a rain tightfitting 180 around a PVC-MC cable.

Referring to FIGS. 24-26, to operate the invention the installer removesan end portion of the PVC jacket 182 from the PVC-MC cable 149 to exposethe armor layer 184 and removes a portion of the armor layer to exposethe conductors 153. The end of the stripped cable 149 is then insertedthrough the loosely assembled electrical fitting 180. Gland nut 32 isthen tightened upon fitting body 22 to secure the cable in a rain tightfit within the electrical fitting. Outbound end 26 of electrical cable149 is secured to an electrical box or panel 147 by locknut 36 againstsealing ring 34 and electrical fitting 180.

With reference to FIG. 27 there is shown a third and preferredembodiment of an electrical fitting 200 for PVC jacketed Metal Clad(PVC-MC) electrical cable. The electrical fitting 200 includes a fittingbody 202 having an inbound end 204 and an outbound end 206. The fittingfurther includes an MC ring 208, a grommet 210, and a bushing 212secured to the inbound end 204 of the fitting body 202 by a gland nut 32and a sealing ring 34 that will be secured to the outbound end 206 by alocknut 36 after the outbound end is connected to an electrical panel orelectrical box (not shown) to create a liquid-tight and concrete-tightfit between the cable, the fitting, and the electrical box. The meaningof the term “liquid-tight” as used herein is that the fitting of thecurrent invention has been rated as a UL listed rain-tight fitting.

As shown in FIGS. 28-29, the fitting body 202 includes a wide inboundend 204 and a substantially narrower outbound end 206. The fitting body202 further includes a flange 38 with flat surfaces or facets 40 thereonenabling gripping by a wrench or similar tool, a threaded nose portion42 extending from the outbound end 206 and a threaded tubular portion 44at the inbound end 204. The fitting body 202 includes an inbound channel46 at the inbound end 204, a necked-down channel 48 formed by a wideramp 50 circumscribing the interior of the body, an inner channel 52having an inner diameter smaller than that of the inbound channel 46,and an outbound channel 54 at the outbound end 206. The body 202includes an outbound opening 57 therein. The fitting includes a flatcable engagement surface 214 on the interior surface 216 of channel 52and a waist portion 218 that is substantially narrower than the inboundend 204 and the flange 38.

With reference to FIGS. 30-33, a deformable grommet 210 according to thepreferred embodiment includes a narrow inbound end 220 with a conicalouter surface 222 and a wide outbound end 224 with a cylindrical outersurface 226 where the angle θ1 of the conical surface 226 with respectto the cylindrical surface 222 is preferably between 20 and 30 degrees.The outbound end 224 of the grommet includes a flat abutment surface228. A bore 230 extends through the grommet 210 which includes a smoothcylindrical interior wall 232.

Referring to FIGS. 34 and 35, MC ring 208 includes a ring body 234having an opening 236 therein and one or more fingers 238 extendingtherefrom. Unlike the first and second embodiments of the fitting, MCring 208 is not a split ring but preferably includes a continuous ringbody 234 with fingers 238 extending from the outer edge of the ringbody. In the third and preferred embodiment of the electrical fittingthe ring body 234 lies in a plane perpendicular with the axial center ofthe ring opening 236 and the fingers 238 each lie in a plane that is ata right angle with respect to the plane of the ring body 234. Thefingers 238 include end portions 240 that are bent inward of the ringbody 234 toward the central axis 235 of the opening 236. The endportions 240 of the MC ring include flat distal ends 242. The MC ring208 is a continuous ring preferably formed of spring steel. Mostpreferably the fingers 238 are situated at 90 degree intervals aroundthe ring body 234.

The conical outer surface 222 on the narrow inbound end 220 the flatabutment surface 228 on the wide outbound end 224 of the grommet 210, incombination with the ring body 234 of the MC ring 208 being in a planeperpendicular with the axial center of the MC ring opening 236 arecritical features of the third and preferred embodiment of theelectrical fitting of the present invention that lead to unexpectedbetter sealing of the fitting against water and concrete. The earlierembodiments of the fitting included a narrowed nose portion on thegrommet 30 b extending into the interior of the MC ring 28 (see FIG. 23)and limiting some portion of the fingers 127 of the MC ring 28 fromclosing toward the central axis. With reference to FIG. 1, in the thirdembodiment, unexpected results have been obtained in that the fingers238 are less impeded in closing on the installed cable and thus makingrequired contact for grounding the MC ring 208 to the installed cableand flat abutment surface 228 of grommet 210 seats against ring body 234of MC ring 208 creating a water-tight and concrete-tight seal.Furthermore, conical outer surface 222 at the inbound end 220 of thefitting 200 bears against conical inner surface 258 (see FIG. 38) insidebushing 212 to provide a further water-tight and concrete-tight seal atthe inbound end 220 of the grommet 210.

Referring to FIGS. 36-39, bushing 212 includes a tubular body 244 havingan inbound end 246 and an outbound end 248 with a collar 250 extendingfrom the inbound end 246 of the body 244. An internal bore 252 extendsthrough the bushing 212. The collar 250 includes an inner surface 254that is coaxial with the center axis 256 of bore 252. Tubular body 244includes a conical inner surface 258 that is formed to substantiallymatch the outer periphery of the inbound end 220 of the grommet 210 (seeFIG. 30). Bushing is preferably constructed of plastic and mostpreferably constructed of polycarbonate.

With reference to FIG. 40, the assembled electrical fitting 200 includesfitting body 202 with gland nut 34 threaded onto the inbound end of thefitting and the locknut 36 threaded onto the threaded nose portion 42 ofthe fitting 200 on the outbound end 206. After being secured to anelectrical box (not shown), sealing ring 34 is held flush and tightagainst the electrical box by the locknut.

With reference to FIG. 41, the electrical fitting 200 is used to connecta PVC jacketed metal-clad (PVC-MC) electrical cable to an electrical boxor panel (not shown). Insertion of a stripped end portion of PVC-MCcable into the inbound end 260 of the fitting along axis 262 andtightening of the gland nut 32 on the inbound end 260 urges the ringbody 234 of the grommet 210 against the MC ring 208 and deforms thegrommet 210 around the cable while at the same time driving the ends 242of the fingers 238 of the MC ring tightly against the armor layer of thecable and grounding the fitting 200 to the cable. By establishing aproper grounding path with the armor, the MC ring 208 electricallygrounds the cable to the fitting body 202 and holds the cable securelywithin the fitting 200 while the deformed grommet 210 affects aliquid-tight and concrete-tight fit between the MC ring 208, grommet210, gland nut 32, and fitting body 202 at the inbound end of thefitting. Collar 250 of bushing 212 extends between the gland nut 32 andthe PVC-MC cable further providing a weather-proof seal between thefitting and the cable at the inbound end 260 of the fitting 200. Locknut36 and sealing ring 34 establish a liquid-tight fit against theelectrical box or panel at the outbound end 206 of the fitting.

PVC-MC cable is rated for installation outdoors and in concrete. Thuselectrical fitting 200 described herein is capable of formingliquid-tight and concrete-tight connections to accommodate PVC-MCelectrical cable in these applications. Furthermore, the electricalfitting 200 can accommodate a wide range of cable sizes. Two nominalsizes of fitting according to the present invention can accommodate acable size range of 14/2 to 4/3, including a cable range of 0.550-inchto 0.890-inch and an overall jacket outside diameter range of 0.670-inchto 0.990-inch.

The description of the present invention has been presented for purposesof illustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A liquid-tight and concrete-tight electricalfitting, comprising: a tubular fitting body including an inbound endwith an inbound bore, and an outbound end with an outbound bore; atubular MC ring in said inbound bore of said fitting body; said MC ringincluding a continuous ring body with an outer edge, an opening havingan axial center, and a plurality of fingers extending from said outeredge of said ring body; a deformable grommet disposed in said bore ofsaid MC ring; a gland nut for urging said grommet and said MC ringwithin said inbound bore of said fitting body; said fingers of said MCring having end portions thereon; and said end portions of said fingersprojecting forward and radially inwardly from the fingers.
 2. Theelectrical fitting of claim 1, wherein said ring body of said MC ring isin a plane perpendicular with the axial center of the opening in the MCring.
 3. The electrical fitting of claim 1, further comprising a locknuton said outbound end of said fitting body; and a sealing ring disposedbetween said locknut and said fitting body.
 4. The electrical fitting ofclaim 1, further comprising a threaded portion on said inbound end ofsaid fitting body.
 5. The electrical fitting of claim 1, furthercomprising a central flange on said fitting body; and facets on saidcentral flange.
 6. The electrical fitting of claim 1, further comprisinga ramped surface circumscribing the interior of said fitting body withinsaid inbound bore.
 7. The electrical fitting of claim 1, wherein saidgrommet further comprises a narrow inbound end; and a wide outbound end.8. The electrical fitting of claim 7, wherein said grommet furthercomprises a conical outer surface on said narrow inbound end; and acylindrical outer surface on said wide outbound end.
 9. The electricalfitting of claim 8, wherein the conical outer surface with respect tothe cylindrical outer surface is at an angle of between 20 and 30degrees.
 10. The electrical fitting of claim 7, wherein said grommetfurther comprises a flat abutment surface on said wide outbound end. 11.The electrical fitting of claim 3, further comprising an inner surfaceon said sealing ring; and a tab extending from said inner surface ofsaid sealing ring to an apex.
 12. The electrical fitting of claim 1,wherein said grommet is constructed of elastomeric material.
 13. Theelectrical fitting of claim 1, wherein the material of construction ofsaid fitting body is selected from the group including zinc alloy,stainless steel, or plated steel; and said MC ring is constructed ofspring steel.
 14. The electrical fitting of claim 1, wherein said glandnut further comprises an inbound end, an outbound end, and an innerperiphery; and a lip including a through bore at said inbound end. 15.The electrical fitting of claim 14, further comprising a bushingdisposed between said gland nut and said grommet; and a flange and anose portion on said bushing.
 16. A liquid-tight and concrete-tightelectrical fitting, comprising: a tubular fitting body including aninbound end with an inbound bore, and an outbound end with an outboundbore; a tubular MC ring in said inbound bore of said fitting body; saidMC ring including a continuous ring body with an outer edge, an openinghaving an axial center, and a plurality of fingers extending from saidouter edge of said ring body; a deformable tubular grommet disposed insaid bore of said MC ring, said deformable tubular grommet including anarrow inbound end and a wide outbound end; a conical outer surface onsaid narrow inbound end of said grommet; a gland nut for urging saidgrommet and said MC ring within said inbound bore of said fitting body;and a ramped surface circumscribing the interior of said fitting bodywithin said inbound bore, said ramped surface adapted for engaging saidfingers of said MC ring.
 17. The electrical fitting of claim 16, furthercomprising a cylindrical outer surface on said wide outbound end of saidgrommet.
 18. A liquid-tight and concrete-tight electrical fitting,comprising: a tubular fitting body including an inbound end with aninbound bore, and an outbound end with an outbound bore; a tubular MCring in said inbound bore of said fitting body; said MC ring including acontinuous ring body; a tubular grommet disposed in said bore of said MCring; a gland nut for urging said grommet and said MC ring within saidinbound bore of said fitting body; a bushing disposed between said glandnut and said grommet; a locknut on said outbound end of said fittingbody; a sealing ring disposed between said locknut and said fittingbody; said sealing ring including an inner periphery and a central axis;a tab extending from said inner periphery on said sealing ring; and anapex aligned along said central axis of said sealing ring.
 19. Theelectrical fitting of claim 18, wherein said MC ring further comprisesan outer edge; an opening having an axial center, and a plurality offingers extending from said outer edge of said continuous ring body. 20.The electrical fitting of claim 19, further comprising a flat abutmentsurface on said grommet; and said ring body of said MC ring is in aplane perpendicular with the axial center of the opening in the MC ring.